Summer Case Study

7/17/2011 | AMRI faculty

A 76-year-old male is carried into the emergency department by a group of family members stating, “He’s been having a heart attack all morning and collapsed into unconsciousness shortly after vomiting.” They further advise that the man had at times that morning complained of difficulty breathing; acted different than usual; and seemed confused and disoriented as he was working in his garden. “Mom said he felt so bad that he refused the iced tea I kept bringing him.”

Question

Can symptoms be atypical and lead to a misdiagnosis?

Physical Exam

The patient appears to be semi-comatose, responding only to very loud or uncomfortable stimuli. His skin feels extremely hot and looks red and dry. There is no sign of breathing difficulty, however, he is breathing very rapidly.

Core temperature = 105.8 F

Cardiac Rate = 172 /min

BP = 66/10

Respiratory frequency = 48/min and shallow

Lung fields auscultate clear and equal bilaterally

Abdomen is soft without anything unusual palpated

Several on the team suggest that the patient has “unstable SVT” because “his heart rate is over 150.” They further suggest that it would be appropriate to perform emergency synchronized cardioversion to convert his arrhythmia. The team leader disagreed and would not allow the intervention.

Another on the team stated that because he was “in the garden” most of the morning without hydration, and considering the outside temperature was in the middle to high 80’s F., it seemed likely that the patient’s condition suggests severe hyperthermia and hypovolemia (i.e. heat stroke). Although much of the presenting history could be cardiac related, the treatment goal should be: (1) cooling and (2) rehydration. The team leader agrees, and the following interventions take place:

1. A large right-sided internal jugular sheath is inserted for fluid administration and central venous pressure (CVP) monitoring. The tip of the device is located just above the right atrium (RA). CVP fluctuates between -2 and 0 cmH20. A rapid 0.9% saline solution is initiated.
2. The patient’s clothing has been removed and ice is applied to the axillary and groin areas as well as introduction of a cooling blanket.

Questions

What are the Cooling options?

1. Cold water bath
2. Evaporative technique rather than immersion
3. Ice packs and cooling blankets

Any cautions?

SHIVERING. Shivering increases body temperature. If it develops, benzodiazepine therapy should be immediately considered.

Case Progression

After receiving a total of 2.5 liters of IV fluid, and the body temperature reaching 99.4 F, the patient is awake, alert, and responsive. His only complaint is “I am so cold.”

His serum electrolyte levels were within normal limits, and his CVP 10 cmH20. BP= 128/72, pulse = 88. Lungs are clear bilaterally with a respiratory frequency of 18 per minute.

The patient’s past medical history was essentially negative. 12 lead ECG was normal. The patient stated that he had not experienced any chest pressure, pain or other cardiac symptoms. He simply remembered feeling agitated, hot, and nauseated and then waking up at the hospital.

Heat Stroke vs. Coronary Syndrome

Initial information from family members contained their untrained assumption regarding the etiology of the patient’s symptoms. Nausea, vomiting, fatigue and syncope are often associated with cardiac events. The uninterrupted history, including sustained exposure to elevated ambient temperature, lack of hydration, and absence of more direct cardiac symptoms, or cardiac history, should tip the balance of suspicion toward heat stroke. Shock was present, and immediate treatment was warranted, and occurred. Complications of shock include end-organ damage. So regardless of cause, shock treatment needs to be the first priority. Careful cardio-respiratory monitoring during fluid resuscitation is mandatory. Development of tachypnea, use of accessory muscles of respiration and auscultation of inspiratory crackles (rales) suggests likely pump failure.

General Post Evaluation Concern

1. Evaluate serum electrolytes and tests of renal function
2. 12-lead ECG, and diagnostics justified by factors such as cardiac history
3. Muscle function tests to identify rhabdomyolysis
4. Radiographic and/or other imaging examinations to rule out or identify organ damage

Miscellaneous Information

Risk Factors for the development of heat stroke:

1. Exposure to elevated ambient temperatures
2. Certain individuals appear to have higher or lower genetic responses to heat
3. Acute exposure vs. chronic (many people can develop great tolerance when exposed over a period of time)
4. Lack of environmental alteration (air conditioning)
5. Pharmaceuticals (beta blockers, diuretics, CNS active agents, methamphetamine and cocaine)
6. Age (the younger person and the older individual statistically respond more dramatically to heat exposure)

Patient Education: (Prevention)

1. Seek shade, use fan or find an air conditioned environment
2. Proactively drink fluids (don’t allow dehydration to occur)
3. Consider hydrating fluids, which replete electrolytes (sports drinks)
4. Wear clothing that is loose fitting and allows for evaporative heat loss
5. Avoid the interior of a closed automobile without functioning air conditioning
6. Never leave children or elderly individuals in a vehicle parked in the sun
7. Limit or avoid physically strenuous activities (establish regular intervals to rest and rehydrate, and stick to the program)

Heat Rash and Cramps

These are often seen as a precursor to heat stroke. Heat rash is skin irritation that occurs during hot, humid weather, and often is seen as small blistered areas or clusters of tiny pimples. Heat cramps are associated with strenuous activity in very warm environments, leading to severe, painful muscle spasms in the extremities and/or abdominal region. Often, the core temperature is not elevated and the skin feels cool and moist.